投稿时间：2020-04-14
修订日期：2020-09-23
网络发布日期：2021-01-08
中文摘要:滇西金厂河铁铜铅锌多金属矿床位于保山地块北部，是西南"三江"成矿带内已知的大中型矽卡岩型矿床之一，具较高的经济价值及重要科研意义。文章在详细野外地质调查和岩相学观察基础上，对不同成矿阶段、特别是含子矿物的流体包裹体进行了研究，同时结合金厂河矿床S、Pb同位素特征，综合分析金厂河矿床成矿流体和物质的来源与演化，探讨矿床的形成机制。对石英内流体包裹体的研究表明，退化蚀变阶段均一温度为165~335℃，盐度w（NaCleq）为1.1%~9.0%；石英硫化物阶段均一温度为151~266℃，WL型包体盐度w（NaCleq）为1.9%~18.9%，S型包体盐度w（NaCleq）为31.9%~33.5%；碳酸盐阶段均一温度为148~250℃，盐度w（NaCleq）为2.6%~9.9%，各阶段均一温度依次降低，盐度先升高，再降低。拉曼光谱分析显示，流体成分为H2O和极少量N2，新发现了子矿物斑铜矿（Cu5FeS4），流体属H2O-NaCl体系。S、Pb同位素特征对比研究表明，金厂河矿床各成矿阶段内硫同位素分馏已达平衡状态，矿石硫化物的δ34S值能代表成矿流体的S同位素组成，用来限定其氧化-还原环境，δ34S值为+2.5‰~+11.1‰、均值+5.65‰，硫源为深部幔源岩浆硫和地层硫构成的混合硫；Pb同位素硫化物组成显示，富铀铅、略亏损钍铅，铅源以上地壳铅为主，另含有少量深部壳源乃至幔源岩浆铅，属造山带铅特征，且与S同位素研究成果基本一致。综合研究认为，成矿系统氧化-还原环境的变化及流体沸腾作用的发生是主要的成矿机制。
Abstract:The Jinchanghe Fe-Cu-Pb-Zn polymetallic deposit in northern Baoshan block is one of the known large and medium-sized skarn deposits in the "Sanjiang" metallogenic belt in southwest Yunnan. It has high economic value and important scientific research significance. On the basis of detailed field geological survey and petrographic observation, the authors studied fluid inclusions in different metallogenic stages, especially the daughter minerals. Meanwhile, the S and Pb isotopic characteristics of Jinchanghe deposit were analyzed. The source and evolution of ore-forming fluid and material were comprehensively analyzed, and the formation mechanism of the Jinchanghe deposit was discussed. The study of fluid inclusions in quartz shows that the homogenization temperature in the degenerative alteration stage is 165~335℃, the salinity w(NaCleq) is 1.1%~9.0%; the homogenization temperature of quartz sulfide stage is 151~266℃, the salinity w(NaCleq) of WL inclusion is 1.9%~18.9%, the salinity w(NaCleq) of S-type inclusion is 31.9%~33.5%, the homogenization temperature of carbonatite stage is 148~250℃, and the salinity w(NaCleq) is 2.6%~9.9%; the homogenization temperature in each stage decreased in turn, and the salinity increased first and then decreased. The fluid belongs to the H2O-NaCl system. The comparative study of S-Pb isotope characteristics shows that S isotope fractionation had reached an equilibrium state in each metallogenic stage of the Jinchanghe deposit. The δ34S value of sulfide in ore can represent the S isotopic composition of ore-forming fluid, which is used to limit the redox environment. The δ34S values are in the range of +2.5‰ to +11.1‰, with an average value of +5.65‰, indicating that the sulfur source was the mixed sulfur composed of deep mantle derived magma sulfur and formation sulfur. The Pb isotope of sulfide is rich in U-Pb, slightly depleted in Th-Pb, and the lead is mainly lead of upper crust, with also a small amount of deep crust and even mantle derived magmatic lead, which belongs to the characteristics of orogenic lead and is basically consistent with the result of S isotope study. A comprehensive study shows that the main metallogenic mechanism is the change of redox environment and the occurrence of fluid boiling.
keywords:geochemistry fluid inclusions S-Pb isotope metallogenic fluids and materials metallogenic mechanism polymetallic deposit Jinchanghe
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基金项目:本文得到云南省科学技术奖-杰出贡献奖项目（编号：2017001）、国家自然科学基金项目（编号：41862009）、云南省基础研究计划-面上项目（编号：2019FB062）和云南省万人计划“青年拔尖人才”专项（编号：20190028）联合资助
引用文本：
李振焕,李文昌,刘学龙,罗应,申颖,刘思晗,陈建航.2020.滇西保山地块金厂河铁铜铅锌多金属矿床成矿机制——基于流体包裹体和硫、铅同位素证据[J].矿床地质,39(6):995~1014LI ZhenHuan,LI WenChang,LIU XueLong,LUO Ying,SHEN Ying,LIU SiHan,CHEN JianHang.2020.Metallogenic mechanism of Jinchanghe Fe-Cu-Pb-Zn polymetallic deposit in Baoshan block, western Yunnan: Evidence from fluid inclusions and S-Pb isotope[J].Mineral Deposits39(6):995~1014
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